Strategic implementation of pulsed oxidation for mitigation of CO poisoning in polymer electrolyte fuel cells

Sarma, Parismita; Gardner, C. L.; Chugh, Sachin; Sharma, Alok; Kjeang, Erik

doi:10.1016/j.jpowsour.2020.228352

Cited by 20 publications

(10 citation statements)

References 36 publications

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“…Figure S11 also shows that the selectivity is significantly affected at a low Cu loading of 6 wt % where CO was detected with a selectivity of around 10%. Moreover, only a few hundred parts per billion CO is permitted in H 2 fuel cells in order to prevent poisoning of the catalyst, making the high-Cu-loaded sample the most promising catalyst …”

Section: Resultsmentioning

confidence: 99%

Selective Photocatalytic Dehydrogenation of Formic Acid by an In Situ-Restructured Copper-Postmetalated Metal–Organic Framework under Visible Light

et al. 2022

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Formic acid is considered as one of the most promising liquid organic hydrogen carriers. Its catalytic dehydrogenation process generally suffers from low activity, low reaction selectivity, low stability of the catalysts, and/or the use of noblemetal-based catalysts. Herein we report a highly selective, efficient, and noble-metal-free photocatalyst for the dehydrogenation of formic acid. This catalyst, UiO-66(COOH) 2 -Cu, is built by postmetalation of a carboxylic-functionalized Zr-MOF with copper. The visible-lightdriven photocatalytic dehydrogenation process through the release of hydrogen and carbon dioxide has been monitored in real-time via operando Fourier transform infrared spectroscopy, which revealed almost 100% selectivity with high stability (over 3 days) and a conversion yield exceeding 60% (around 5 mmol•g cat −1•h −1 ) under ambient conditions. These performance indicators make UiO-66(COOH) 2 -Cu among the top photocatalysts for formic acid dehydrogenation. Interestingly, the as-prepared UiO-66(COOH) 2 -Cu hetero-nanostructure was found to be moderately active under solar irradiation during an induction phase, whereupon it undergoes an in-situ restructuring process through intraframework cross-linking with the formation of the anhydride analogue structure UiO-66(COO) 2 -Cu and nanoclustering of highly active and stable copper sites, as evidenced by the operando studies coupled with steady-state isotopic transient kinetic experiments, transmission electron microscopy and X-ray photoelectron spectroscopy analyses, and Density Functional Theory calculations. Beyond revealing outstanding catalytic performance for UiO-66(COO) 2 -Cu, this work delivers an in-depth understanding of the photocatalytic reaction mechanism, which involves evolutive behavior of the postmetalated copper as well as the MOF framework over the reaction. These key findings pave the way toward the engineering of new and efficient catalysts for photocatalytic dehydrogenation of formic acid.

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Section: Resultsmentioning

confidence: 99%

Selective Photocatalytic Dehydrogenation of Formic Acid by an In Situ-Restructured Copper-Postmetalated Metal–Organic Framework under Visible Light

et al. 2022

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“…Their results show that the poisoning from a fuel stream containing 10 ppm CO but with only 40% hydrogen content is equivalent to that of a hydrogen stream containing 100 ppm CO. The impact of fuel dilution on the performance of a PEFC using anode recirculation clearly needs to be considered when the fuel contains even low levels of CO in order to optimize purge times and volumes as well as the choice of the CO mitigation strategy [15,28] used including operating conditions such as pulse frequency and/or air bleed rate.…”

Section: Exponential Accumulation-diffusion Through the Membranementioning

confidence: 99%

Accumulation of Inert Impurities in a Polymer Electrolyte Fuel Cell System with Anode Recirculation and Periodic Purge: A Simple Analytical Model

2022

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Anode recirculation with periodic purge is commonly used in polymer electrolyte fuel cell systems to control the accumulation of nitrogen, water, and other impurities that are present in the fuel or diffuse through the membrane from the cathode compartment. In this work, we develop a simple, generalized analytical model that simulates the time dependence of the accumulation of inert impurities in the anode compartment of such a system. It is shown that, when there is transport out of the anode chamber, the inert species is expected to accumulate exponentially until equilibrium is reached when the rate of inert entering the anode in the fuel supply and/or via crossover from the cathode is balanced by the rate of leakage and/or crossover to the cathode. The model is validated using recently published experimental data for the accumulation of N2, CH4, and CO2 in a recirculated system. The results show that nitrogen accumulation needs to be taken into account to properly adjust system parameters such as purge rate, purge volume, and recirculation rate. The use of this generalized analytical model is intended to aid the selection of these system parameters to optimize performance in the presence of inerts.

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“…To meet the ISO standards, the cost of the H 2 increases, which makes the PEM fuel cell more expensive. Various techniques such as CO electrocatalyst at the anode side, increasing the operating temperature of PEM fuel cell, elevating cathode backpressure, and introducing oxygen into the fuel gas flow have been proposed to minimize the effects of CO on PEM fuel cell performance 50,128 …”

Section: Parameters Influencing the Performance Of Pem Fuel Cellmentioning

confidence: 99%

Factors influencing the performance of PEM fuel cells: A review on performance parameters, water management, and cooling techniques

Singh

Oberoi

Singh

2021

Intl J of Energy Research

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Summary This paper addresses the effects of critical parameters that affect the performance and lifespan of proton exchange membrane (PEM) fuel cells. Amongst all, control of excess water content and dehydration in PEM fuel cells is the major issue under various operating conditions. Therefore, their effects on cathode, anode, gas diffusion layer (GDL), catalyst layer (CL), and flow channels are summarized in the initial part of this paper. Various active cooling strategies such as air cooling, liquid cooling, and phase change method to extract the waste heat from the stack are represented. The lateral part of this paper throws light on the role of heat pipes, working fluid, and the effect of the addition of nanofluid with pertinent filling ratio (FR) in cooling of PEM fuel cells. This work is intended to aid the selection of cooling methods for PEM fuel cells through the consideration of the variety of affecting parameters preceding major expenditure for wide‐scale production. In future, cost comparison associated with the cooling techniques of the fuel cell would be evaluated.

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Strategic implementation of pulsed oxidation for mitigation of CO poisoning in polymer electrolyte fuel cells

Cited by 20 publications

References 36 publications

Selective Photocatalytic Dehydrogenation of Formic Acid by an In Situ-Restructured Copper-Postmetalated Metal–Organic Framework under Visible Light

Selective Photocatalytic Dehydrogenation of Formic Acid by an In Situ-Restructured Copper-Postmetalated Metal–Organic Framework under Visible Light

Accumulation of Inert Impurities in a Polymer Electrolyte Fuel Cell System with Anode Recirculation and Periodic Purge: A Simple Analytical Model

Factors influencing the performance of PEM fuel cells: A review on performance parameters, water management, and cooling techniques

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